Pumps for fluids



y 20, 1965 J. c. BOWEN ETAL 3,195,806

PUMPS FOR FLUIDS Filed May 31. 1963 INVENTORS JOHN C. BOWEN ATTORNEYUnited States Patent 3,195,806 PUMPS FOR FLUIDS John C. Bowen,Davisville, and Robert C. Wolf, Hatboro,

Pa., assignors to Pressure Products Industries, Inc., Hatboro, Pa., acorporation of Pennsylvania Filed May 31, 1963, Ser. No. 284,538 7Claims. (Cl. 230-69) This invention relates to pumps for fluids and moreparticularly to pumps for the delivery of small quantities of gas atvery high pressures.

Compressors for delivering gas at very high pressures, and employingdiaphragms and pistons, are currently in use but no apparatus isavailable for the delivery of small quantities of a specific gas at veryhigh pressures.

It is the principal object of the present invention to provide a pumpfor fluids in which the pumping action is effected by expansion of thefluid by heating the fluid in a chamber.

It is a further object of the present invention to provide a pump inwhich the pumping action is effected by heating the fluid in a chamberwhich chamber serves as a resistance heating element.

It is a further object of the present invention to provide a pump forfluids which is simple in construction, free from operatingdifliculties, and with which small quantities of a specific gas at highpressure can be easily obtained.

It is a further object of the present invention to provide a pump of thecharacter aforesaid in which the pumping space comprises anintermittently heated capillary tube.

It is a further object of the present invention to provide a pump fordelivery of small quantities of gas at very high pressures in which thepumping space comprises a capillary tube which is quickly heated andcooled in a continuous cycle.

It is a further object of the present invention to provide a pump fordelivery of small quantities of gas at very high pressures in which thepumping space comprises a capillary tube and the tube serves as aresistance heating element for heating the fluid therein.

Other objects and advantageous features of the invention will beapparent from the description and claims.

The nature and characteristic features of the invention will be morereadily understood from the following description taken in connectionwith the accompanying drawing forming part thereof, in which:

The figure is a diagrammatic view illustrating the pump in accordancewith the invention.

It should, of course, be understood that the description and drawingherein is illustrative merely and that various modifications and changescan be made in the structure disclosed without departing from the spiritof the invention.

In accordance with the invention gas of any desired type or kind, andfrom any suitable source, is delivered through an inlet check valve to aheating vessel which serves as a pumping chamber, and from the heatingvessel is delivered through a delivery check valve to the high pressuregas receiver. The heating vessel is alternately heated and cooled. Forpurposes of heating the vessel advantageously serves as an electricalresistance heater. For purposes of cooling air or other cooling fluidmay be circulated over the exterior of the heating vessel.

Referring now more particularly to the drawing, a source 10 of gas to bedelivered is illustrated which can be a gas tank or other receptacle ofgas previously compressed to a predetermined level. The gas at thesource may be nitrogen, hydrogen, air, or other gas to be compressed.

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The source 10 of gas is connected by a pipe 11 to an inlet check valve12 of any preferred type capable of operation at very high pressures.The check valve 12 is connected to the heating vessel 15. The heatingvessel 15 is connected to a delivery check valve 16 which in turn isconnected by a pipe 17 to the high pressure gas receiver 18. The checkvalves 12 and 16 and the connections to the heating vessel 15 can bemounted within a suitable housing 19.

The heating vessel 15 which provides the pumping chamber is preferablyof capillary tubing capable of serving as an electrical conductor andresistance heater, and in a specific embodiment of the invention,capillary tubing of a length of about one hundred feet in an open coilsealed at one end, gave satisfactory results.

In order to provide the energy input to heat the vessel 15, one end ofthe capillary tubing is connected by a conductor 20 to a switch contact21, the other end of the capillary tubing being connected by a conductor22 to ground.

A source 23 of electrical energy is connected to ground by a conductor24 and by a conductor 25 to a switch arm 26.

An electric motor driven fan 30 is provided having a conductor 31extending to ground and a conductor 32 extending to a switch contact 33for selective engagement by the switch arm 26.

The fan 30 has a fan blade 34 for directing a stream of cooling fluid,such as atmospheric air, over the exterior of the heating vessel 15. Ahousing 35 can be provided to aid in directing the cooling fluid flow.

The source 23 of electrical energy can be connected as desired to theheating vessel 15 to heat the same by movement of the switch arm 26 toalternately engage the contacts 21 and 33. This movement of the switcharm 25 can be effected in any desired manner such as by a variable oradjustable motor driven timer 36.

The mode of operation will now be pointed out.

Assuming a sufiicient pressure of fluid at the source 10, the fluid isdelivered to fill the pipe 11, the heating vessel 15, the pipe 17 andthe receiver 18.

If now, heat is applied to the heating vessel 15, expansion of the fluidin the heating vessel 15 occurs and part of the fluid is delivered pastthe delivery check valve 16 and through the pipe 17 to the gas receiver18.

Heating of the vessel 15 is effected upon engagement of the switch arm26 with the contact 21 and the resistance heating by the current appliedon the capillary tube employed for the vessel 15.

Upon completion of the heating, the current supply to the vessel 15 isinterrupted by separation of the switch arm 26 from the switch contact21.

While the vessel 15 might be permitted to cool without outsideassistance, it is preferred, in the interest of more rapid operation, toemploy the motor driven fan 30 to apply a positive flow of cooling fluidon the exterior of the vessel 15. Upon separation of the switch arm 15from the switch contact 21 it is accordingly preferred to move theswitch arm 26 to engage the switch contact 33 to actuate the fan 30 andits fan blade 34.

Upon cooling of the heating vessel 15, additional fluid from the source10, delivered through the pipe 11 will pass the check valve 12 andrefill the heating vessel 15.

The heating cycle can then be repeated.

The operation of the pump heretofore described for gases is dependentupon the gas laws and the temperature relation:

where T is the initial or input gas temperature in abt s a a J v solutetemperature units and T is the outputgas temperature expressed in thesame units.

It will be seen that doubling or tripling of thetemperature differencecan be readily effected within practicable operating ranges:Forfexample, heating the gas irithe 7 means inclu ding electric currentapplying members connected to said'chamber'at spaced locations forheating said chamber for selected time intervals, and means for Vcooling said chamber for selected time intervals intervessel 15 to atemperature of theorder of 600 F. (1060 v V F. abs.) has beenfoundsatisfactory' fora'specific opera 1 tion.

The apparatus 'of'the' present invention has been found to be suitablefor elfecting deliveryof 'small quantities of gas at exceedingly highpressures which may range up to 50,000 to 100,000 p.s.i. I We claim:

' 1. A pump for fluidsEcomprising a"connecti'on to a source of fluid, aninlet valve member connected to said connection,:a fluid"chambericonnected to said valve meme her and having a wall of electricalconductive material, a delivery valve'member connected to saidfluidcch'am posed between said heating time intervals.

6. A pump for; fluids comprisinga connection to a seurce of-fluid, afluid delivery connection, a fluid chamber'connected to saidconnections, said fluid chamber comprising an electrically conductivecapillarytube, inlet and delivery valve members in said connections,means for heating said chamber for selected time intervals said b meansfor heating including electric current applying members connected tosaid capillary tube, and means for cool- ,in'g said ch'amber forselected time intervals interposed between said heatingtime intervals.

17- A pump for fluids comprising a" connection to a 7 source of'fluid, afluid delivery. connection',; a fluid chamber connected tosaidconnections andcomprising an elecber, and means fort intermittentlyheating, said'qchamber a for expansion of fluid therein and deliveryof'fluidthrough the delivery valve member, said'means including a sourceof electrical energy and, connections :to spaced portions r ofsaidwallforapplying current thereto from said source 7 for heating saidwall. a I 1 I 2. A pump for fluidsas defined in claim l'fin which saidchamber isa capillary tubef v 3. A pump for fluids as defined in claim 1in which said chamber is a coiledcapillarytube.

4. A pump for fluidsas definedin claim 1 also having trically conductivecapillaryrtube, iinlet and delivery valve members in said connections,means for heating said chamber forgselected timeiin'tervals includingelec tric' current applying mem ers connected to said capillary tube,and means for cooling saidchamber for selected time intervals interposedbetwen saidheatin'g timeintervalsincluding a motor driven device fordelivering cooling fluid in'contact with saidftube.

means for intermittently cooling said chamber in intervals betweencurrent application for heating; 7 I

V 5. 'A pump for fluids comprising a connection to. a

source of fluid, a fluid deliveryconnection, tin-electrically conductivefluid chamber connected 7 to said connections,

inlet and delivery valve members in said. connections,

- References Cited'by-the Examiner v UNITED STATES PATENTS 1,630,943'S/ZT'l-Iu'tton s 23069 2,510,427 6/50 S'ou'cie' 230-69

1. A PUMP OF FLUIDS COMPRISING A CONNECTION TO A SOURCE OF FLUID, ANINLET VALVE MEMMBER CONNECTED TO SAID CONNECTION, A FLUID CHAMBERCONNECTED TO SAID VALVE MEMBER AND HAVING A WALL OF ELECTRICALCONDUCTIVE MATERIAL, A DELIVERY VALVE MEMBER CONNECTED TO SAID FLUIDCHAMBER, AND MEANS FOR INTERMITTENTLY HEATING SAID CHAMBER FOR EXPANSIONOF FLUID THEREIN AND DELIVERY OF FLUID THROUGH THE DELIVERY VALVEMEMBER, SAID MEANS INCLUDING A SOURCE OF ELECTRICAL ENERGY ANDCONNECTIONS TO SPACED PORTIONS OF SAID WALL FOR APPLYING CURRENT THERETOFROM SAID SOURCE FOR HEATING SAID WALL.